Explained: How Solar Storms Cause Colourful Auroras On Earth

From northern Europe to Australia's Tasmania, the sky-gazers last night witnessed stunning auroras that painted the skies in pink, green, and purple hues.

Auroras illuminated the skies across many regions on Saturday. This was the second time in a row on May 11 that auroras lit up the skies across swaths of the planet. Why do we get auroras on Earth after eruptions occur on the Sun? A thread. ????⬇️⬇️⬇️(Images:Left: a solar flare captured by NASA's Solar Dynamics Observatory.Right: Aurora seen from Lummi Island, Washington, at 10:54 p.m. PT on May 10, 2024. Credit: Jeff Carter) pic.twitter.com/0seln79n0p There are two things we call solar eruptions: solar flares and coronal mass ejections (CMEs). They often occur together, but not always.Solar flares are intense flashes of light — a result of the Sun's complex magnetic fields abruptly rearranging themselves. pic.twitter.com/s6qYXQIkw8 Coronal mass ejections (CMEs) are giant clouds of solar particles laced with magnetic fields that escape from the Sun. These giant clouds can travel anywhere in the solar system, including to us here on Earth. pic.twitter.com/HiuoTtSe3W Solar flares reach us quickly — light only takes about 8 minutes to reach Earth.Because CMEs are made up of particles, they may take days to reach us.But when they do, they can set the aurora alight. pic.twitter.com/0L0WDJmwWy When a CME collides with Earth's magnetic field, it can dump solar particles into near-Earth space.These particles follow Earth's magnetic field lines as they dive into our atmosphere in a “ring” around the poles called the auroral oval. pic.twitter.com/xT4U7SG3Tq The incoming particles strike gases in our atmosphere, causing them to heat up and glow: the aurora.The colors depend on the type of gas and its altitude. Oxygen glows red or blue; nitrogen can be green, blue, or pink.Image Credit: NASA/Aurorasaurus pic.twitter.com/9uqicvBPSl Powerful, repeated eruptions like those we've had recently can widen the auroral oval, pushing aurora to lower latitudes. Last night, northern lights were reported as far south as the Bahamas!Here's last night's view from Bear Lake, Utah. Credit: NASA/Bill Dunford pic.twitter.com/E5BnrvqqpP

This spectacular celestial show, which is usually confined to the far northern reaches of the planet and is called "northern lights”, is triggered by a powerful solar storm.

A report by news agency AFP stated that this powerful solar storm could also continue on Sunday.

Why do we get auroras?